Abstract: :
Purpose: To develop a metric technique assessing the morphologyof the zonular apparatus, measure size, distribution and anchoragelocation of individual zonules with respect to the lens equator,in function of age, sex, and species.Methods: 10 human (55–82 y/o, 3–5 days PMT) and7 cynomolgus (4–7 y/o, 1 to 3.5hrs PMT) postmortem eyeswere used. After 24hrs formalin fixation, an aluminum ring machinedto conform the globe was bonded with cyanoacrylate to the scleralwall at the level of the crystalline lens, and using an operationmicroscope, the posterior pole and corneoscleral rim were sectionedand vitreous and iris removed. The metal mounted tissue sectionwas post fixed for >24hrs in 2.5% glutaraldehyde, post–fixedin osmium, transferred in 5 different grades of alcohol, washedin PBS twice for 5 min and underwent stepped critical point–drying.To assess the posterior face of the zonular apparatus, the hyaloidmembrane was peeled after completion of the fixation processusing #5 jeweler forceps under the operation microscope at 20x.The ring–tissue assembly was gold coated.Results: The technique was successful in 14 of 17 eyes showingthe zonular apparatus under normal physiological tension. Eventhough degassing was done in a gradual manner, splits occurredin lenses with high PMT but not in fresh ones. Measured at themiddle–point between capsule anchorage and ciliary bodyprocesses, zonule bundle diameter varied from 6 to 35 µmin human and 3.5 to 50µm in cynos. At the lens capsuleanchorage zone, they split in finer strands varying from <1to 7 µm in human and <0.5 to 15µm in cynos. Theanterior zonules were larger than the posterior zonules in humanthan in cynos. The density of zonules was approximately 10 %higher in cynos than in human. The technique will also be usedon paired eyes to study the effect of ex–vivo lens stretching(Denham et al, ARVO’02) and lens refilling (Parel et al,ARVO’03).Conclusions:This new technique is reproducible and allows clearmorphological assessment of the zonular apparatus. CR: NoneSupport: NIH EY14225; Vision CRC Sydney, Australia; FloridaLions Eye Bank; Research to Prevent Blindness, Diabetic ResearchInstitute (Dr N Kenyon); UM DVR (Dr P Gulett and Dr B Collins);Henri and Flore Lesieur Foundation.